Mozilla -> location bar history

For some reason Mozilla fails to record any history in
my location bar. It is empty at any given time.
It has not always been like this, but I do not know
if this problem is a result of some cron apt-get upgrade
or my own fat fingers. Going into preferences, the Clear button
is also grey'd out.

Anyone know how to fix? (Aside from apt-get remove -> apt-get install)

-mike